The present invention relates to a valve for regulating fluids, and in particular, a fuel injection valve for a storage injection system.
Many forms of valves for regulating fluids are known in the state of the art. In particular, valves are known, which are formed with a second supply or feed to increase the closing speed of the valve, which makes possible a faster closing of a control valve of a valve and thereby also increases the closing speed of the injection valve.
However, disadvantages are associated with these known valves, such as that with these known valves, only outwardly opening valves can be used, in which the piezo actor and the control valve work in the same direction. Therefore, the known valves required a relatively large total height, so that the valves have a relatively large longitudinal extension. Since particularly in engine chambers, only a relatively small amount of space is available, it is desirable to have a compact injection valve.
The valve of the present invention for regulating fluids, in contrast, has the advantage that it has an especially short closing time and a control valve that is formed as an inwardly opening valve. Therefore, the inventive valve can be very compactly formed and has only a relative small longitudinal extension. With the invention valve, the operating directions of the piezo actor and the control valve are opposite. In other words, when the piezo actor is regulated and extends in one direction, a control valve of the valve is operated in such a manner that it moves in the opposite operating direction of the piezo actor, and thereby lifts a valve member from a valve seat, in order to make possible an opening of the valve through creating a connection with a low pressure region. In order to make possible a faster closing of the valve, a second supply throttle is provided, which is connected with a valve chamber of the control valve. The second supply throttle of the valve chamber is connected directly with a high-pressure line.
Preferably, a second valve seat opposite to the first valve seat is provided on the control valve, so that in the opened state of the control valve, the connection from the valve chamber to the high pressure line via the second supply throttle on the second valve seat is closed. In this manner, the leakage loss with an opened control valve is minimized.
Preferably, a plate-shaped element is provided on the control valve for closing the second valve seat, and the second valve seat is formed as a flat seat. Thus, the control valve can be simply and compactly formed.
In order to have the least possible number of parts, the plate-shaped element for closing the second valve seat is also formed to operate as a spring seat for an opening spring of the control valve.
According to one embodiment of the invention, the converter of the valve is formed to regulate fluids as a hydraulic converter. The hydraulic converter includes a first piston, a second piston, and a fluid chamber disposed in a working direction between the two pistons. It should be noted that the hydraulic converter could also be formed as a hydraulic coupler, which provides no conversion of the piezo actor lift, rather, only equalizes temperature-related length changes of the piezo actor.
It is especially advantageous if the hydraulic converter is formed so that the two pistons have opposite directions of movement relative to one another. In this manner, an implementation of the movement of the control valve counter to a movement of the piezo actor can be easily realized.
In order to provide an especially cost-effective manufacture, a bearing is arranged on the second piston, which is connected with a fluid chamber of the hydraulic converter. The bearing is therefore fixedly connected, for example, by means of a press-fit, with the second piston. It should be noted that instead of a bearing, a one-piece piston could be used, which is formed as a stepped-off piston with different diameters.
It is also advantageous if the bearing of the second piston, or the second, stepped piston also is formed to act as a spring seat for a sealing spring of the hydraulic converter.
Advantageously, the sealing spring for the hydraulic converter is also used simultaneously as a biasing spring for the actor. In this connection, it is preferred that the first piston is formed as a cup-shaped piston, on whose inner base surface the sealing feather engages and whose outer base surface is connected with the piezo actor. Preferably, the second piston of the hydraulic converter is lead to the cylinder-shaped inner walls of the first piston. Thus, an especially compact construction of the inventive valve can be achieved.
The inventive valve is especially suited for use as a fuel injection valve in a storage injection system. Through the compact construction and the fast closing speed of the inventive valve, the fuel use and the exhaust emission can be positively affected.